Question

Evaluate S5 for 300 + 150 + 75 + … and select the correct answer\below.
18.75
93.75
581.25
145.3125

Answer 1

@imqwerty

Answer 2

alright what kind of series do you think it is

Answer 3

geometric series

Answer 4

hi guy's

Answer 5

yes correct
and the formula for the sum till \(n^{th}\) term of a geometric series is this-

\(\large Sum=a \left( \frac{1-r^n}{1-r} \right)\)

here \(a\) is the 1st term
and r is the common ratio

Answer 6

gm, find, first 5 term of this series

Answer 7

find common ratio, and than find term's of this series,
and after this use formula as mentioned aove in @imqwerty comment

Answer 8

what would the common ratio be?

Answer 9

the common ratio is the ratio of any two consecutive terms
like this->

\(common ~ratio= \large \frac{2^{nd}~term}{1^{st}~term}\)

Answer 10

devide first term of the series with second term, and the answer would be yours C.R.

Answer 11

sorry, second by first,

Answer 12

mistake, excuses

Answer 13

you can take any two consecutive terms
so this is also correct-
\(common~ratio=\large \frac{3^{rd}~term}{2^{nd}~term}\)

Answer 14

so 0.5?

Answer 15

yes right

Answer 16

yes :)

Answer 17

Using the formula you put what do i plug in for the n? 5?

Answer 18

yeah
you need to find "\(S5\)" meaning sum till the 5th term
so yeah \(n=5\) in our case :)

Answer 19

I'll tag you if I need help on more. Thanks qwerty :D

Answer 20

anytime ;)